how to take images with multiple cameras with Script?
You might want to edit the os.path.join to get an OS independent tmp directory or set something else.

import bpy
import os

scene = bpy.context.scene

for ob in scene.objects:
    if ob.type == 'CAMERA':
        bpy.context.scene.camera = ob
        print('Set camera %s' % ob.name )
        file = os.path.join("C:/tmp", ob.name )
        bpy.context.scene.render.filepath = file
        bpy.ops.render.render( write_still=True )